1. Field of the Invention
This invention relates to a developer regulating device in developing apparatus. More particularly, it relates to developing apparatus which can detect the quantity of a developer in a developer container and give notice of the replenishment of the developer.
2. Description of the Prior Art
An electrostatic latent image in electrostatic recording equipment is developed by developing apparatus. As the developing apparatus, dry type ones employing powder developers have been adopted in recent years. The powder developers include a one-component developer in which a toner itself assumes magnetism, and a two-component developer in which a toner and a magnetic carrier are mixed. By developing the electrostatic latent image, the developer in the developing apparatus is consumed. It is accordingly necessary that the remaining quantity of the developer be detected so as to replenish the developer. Most of the consumption in the two-component developer is the toner. In the developing apparatus employing the two-component developer, therefore, it suffices to replenish only the toner in many cases.
As a developer regulating device in the developing apparatus employing the two-component developer, there has heretofore been proposed a detection system in which a change in the magnetic permeability of the developer is detected. An example thereof is U.S. Pat. No. 3,572,551 (Inventors: Gillespie et al, application Ser. No.: 811,132, Filed: Mar. 27, 1969, Patented: Mar. 30, 1971, Assignee: RCA Corporation). Such a regulating device, however, has the disadvantage of requiring a mechanism for sampling the developer and becoming complicated.